Drug targeting and release is an area of intense research. Continuous efforts are being made to develop controlled drug release system because appropriate dosage decides the therapeutic efficiency of the drugs. The main target of the current drug delivery research are specific targeting and delivery of drugs, reduction in toxicity while maintaining the therapeutic effects, greater safety and biocompatibility. Drug delivery systems developed by nanotechnology researchers include polymeric micelles, polymeric nanoparticles, magnetic nanoparticles, liposomes and dendrimers. Of all these iron oxide based magnetic nanoparticles are of interest in drug delivery due to the benefit of targeting the carrier by an external magnetic field. Iron oxide nanoparticles coated with suitable surfactants also act as a multifunctional platform which can be simultaneously used as contrast agents in magnetic resonance imaging (MRI), magnetic hyperthermia and drug delivery. Even though there are various reports on the biomedical application of magnetite nanoparticles, delivery of hydrophobic drug without losing its therapeutic efficacy is of importance. The delivery of these drugs to the target site is suggested through different carriers like polymeric micelles, silica nanoparticles and cyclodextrin derivatives. Of these cyclodextrins which have a hydrophobic cavity can be an efficient candidate for entrapment of hydrophobic drug.
Article titled, “Novel method for preparation of β-cyclodextrin/grafted chitosan and it's application” by K. El-Tahlawy et. al in Carbohydrate Polymers, 2006, 63, 385-392 reports a novel technique for preparation of β-cyclodextrin-grafted chitosan by reacting β-cyclodextrin citrate (β-CD citrate) with chitosan. β-Cyclodextrin citrate was synthesized by esterifying β-cyclodextrin (β-CD) with citric acid (CA) in presence or absence of sodium hypophosphite as a catalyst in a semidry process. Chitosan and β-cyclodextrin/grafted chitosan, having different molecular weights, were evaluated as antimicrobial agents for different microorganisms such as, Bacillus megaterium, Pseudomonas fragi, Bacillus cereus Staphylococcus aureus, Escherichia E coli and Aeromonas hydra. 
Article titled, “Magnetic Nanoparticles Grafted with Cyclodextrin for Hydrophobic Drug Delivery” by Shashwat S. Banerjee and Dong-Hwang Chen in Chem. Mater. 2007, 19, 6345-6349 reports a novel magnetic nanocarrier, cyclodextrin (CD)-citrate-gum arabic modified magnetic nanoparticles (GAMNPs), for hydrophobic drug delivery fabricated by grafting the citrate-modified CD onto the GAMNPs via carbodiimide activation. The product had a mean diameter of 14.6 nm and a mean hydrodynamic diameter of 26.2 nm. The amount of CD grafted on the GAMNPs was determined to be 28.7 mg/g by the thermogravimetric analysis. The feasibility of using CD-citrate-GAMNPs as a carrier for hydrophobic drug delivery was demonstrated by investigating the formation of the inclusion complex and the in vitro release profile using ketoprofen as a model hydrophobic drug. Also, the presence of surfactant (sodium dodecyl sulfate, SDS) led to a decrease in the inclusion of ketoprofen because the linear structure of SDS made it easier to enter the cavity of CD as compared with the less linear ketoprofen.
Article titled, “Multi-functional magnetic nanoparticles for magnetic resonance imaging and cancer therapy” by Murali M. Yallapu, Shadi F. Othman, Evan T. Curtis b, Brij K. Gupta, Meena Jaggi, Subhash C. Chauhan in Biomaterials 32 (2011) 1890-1905 reports a multi-layer approach for the synthesis of water-dispersible superparamagnetic iron oxide nanoparticles for hyperthermia, magnetic resonance imaging (MRI) and drug delivery applications. In this approach, iron oxide core nanoparticles were obtained by precipitation of iron salts in the presence of ammonia and provided b-cyclodextrin and pluronic polymer (F127) coatings. This formulation (F127250) was highly water dispersible which allowed encapsulation of the anti-cancer drug(s) in b-cyclodextrin and pluronic polymer for sustained drug release. The F127250 formulation has exhibited superior hyperthermia effects over time under alternating magnetic field compared to pure magnetic nanoparticles (MNP) and b-cyclodextrin coated nanoparticles (CD200). Additionally, the improved MRI characteristics were also observed for the F127250 formulation in agar gel and in cisplatin resistant ovarian cancer cells (A12780CP) compared to MNP and CD200 formulations. Furthermore, the drug loaded formulation of F127250 exhibited many folds of imaging contrast properties. Due to the internalization capacity of the F127250 formulation, its curcumin-loaded formulation (F127250-CUR) exhibited almost equivalent inhibition effects on A2780CP (ovarian), MDA-MB-231 (breast), and PC-3 (prostate) cancer cells even though curcumin release was only 40%. F127250-CUR also exhibited haemo compatibility, suggesting a nanochemotherapuetic agent for cancer therapy.
Article titled, “Water-dispersible ascorbic-acid-coated magnetite nanoparticles for contrast enhancement in MRI” by V. Sreeja, K. N. Jayaprabha and P. A. Joy in Applied Nanoscience April 2015, Volume 5, Issue 4, pp 435-441 (First online on April 2014) reports Superparamagnetic iron oxide nanoparticles of size ˜5 nm surface functionalized with ascorbic acid (vitamin C) form a stable dispersion in water with a hydrodynamic size of ˜30 nm. NMR relaxivity studies show that the ascorbic-acid-coated superparamagnetic iron oxide aqueous nanofluid is suitable as a contrast enhancement agent for MRI applications, coupled with the excellent biocompatibility and medicinal values of ascorbic acid.
Article titled, “Curcumin Encapsulated Superparamagnetic Iron Oxide Based Nanofluids for Possible Multifunctional Applications” by K. N. Jayaprabha and P. A. Joy in J. Nanofluids, 2014, 3, 1-7 reports synthesis of Curcumin coated ultra-small superparamagnetic iron oxide nanoparticles (USPIONs) of size 3 nm. Relaxivity measurements using nuclear magnetic resonance (NMR) technique showed values similar to that reported for other established superparamagnetic iron oxide based contrast enhancement agents in magnetic resonance imaging (MRI). Thus, curcumin coated USPIONs are suitable as contrast enhancement agent in MRI along with the medicinal and fluorescent property of the curcumin shell, indicating the possible multifunctional applications.
Article titled, “Cyclodextrin-curcumin self-assembly enhances curcumin delivery in prostate cancer cells” by Murali Mohan Yallapua, Meena Jaggi, Subhash C. Chauhan in Colloids and Surfaces B: Biointerfaces 79 (2010) 113-125 reports a cyclodextrin (CD) mediated curcumin drug delivery system via encapsulation technique. Curcumin encapsulation into the CD cavity was achieved by inclusion complex mechanism. Curcumin encapsulation efficiency was improved by increasing the ratio of curcumin to CD. An optimized CD-curcumin complex (CD30) was evaluated for intracellular uptake and anti-cancer activity. Cell proliferation and clonogenic assays demonstrated that cyclodextrin-curcumin self-assembly enhanced curcumin delivery and improved its therapeutic efficacy in prostate cancer cells compared to free curcumin.
US20140369938A1 relates to curcumin coated magnetite nanoparticles, which are biocompatible, stable curcumin or its derivatives coated ultra-small superparamagnetic iron oxide nanoparticles (USPION) for biomedical applications. The invention further relates to a simple one-pot process for the synthesis of biocompatible, stable curcumin or its derivatives coated ultra-small superparamagnetic iron oxide nanoparticles in absence of a linker or binder. The average crystallite sizes of uncoated and coated samples are in the range of 7 nm and 4 nm respectively.
Article titled “A novel curcumin-artemisinin coamorphous solid: physical properties and pharmacokinetic profile” by Kuthuru Suresh, M. K. Chaitanya Mannava and Ashwini Nangia in RSC Adv., 2014, 4, 58357-58361 reports a curcumin-artemisinin coamorphous solid (1:1) prepared by rota-vaporization and a dramatic increase in the pharmacokinetic profile of curcumin.
But there is a still a need in the art to provide a suitable carrier for hydrophobic drugs that provides a targeted delivery of the drug to the site of action, such that the carrier possesses a cavity that is suitable to hold or lodge a small hydrophobic molecule such as a drug. It would be advantageous if such a carrier further can possess improved loading efficiency with regard to the small hydrophobic molecule.